Current systems and methods used for the radio remote control of locomotives, particularly in switching yards, typically employ a microprocessor based controller mounted onboard the locomotive and one or more one-way portable radio transmitters or operator control units associated with the controller to allow one or more operators to control the locomotive. Numerous remote control locomotives are normally used simultaneously in a given switching yard or remote control zone. Current radio remote control systems employing asynchronous transmission methods can only handle about 5 to 7 locomotives with associated transmitters on a single simplex wireless channel or two half duplex wireless channels (repeater system) when operating in a given location and with a given command response time. Because useable radio frequencies are limited, this effectively limits the number of remote control locomotives that can be operated simultaneously in a given switching yard or remote control zone.
Moreover, remote control systems for locomotives currently in use also typically employ only one-way data communication between the onboard controller and the operator control units, and therefore can perform only a limited number of operational and safety functions.